1. Field of the Invention
The present invention relates to an electrostatic chuck device of adsorbing and processing a semiconductor.
2. Description of Related Art
In a system of producing semiconductors used for dry process or plasma coating in semiconductor production, it has been used halogen-based plasma such as F, Cl or the like having high reactivity for etching or cleaning. It is thus required, for a member equipped to such semiconductor production system, high corrosion resistance, so that it has been generally used a member of an anti-corrosive metal such as aluminum with alumite treatment, HASTELLOY or the like or a ceramic material. Especially, it is necessary high corrosion resistance and low particle generation properties for an electrostatic chuck or heater member supporting and fixing an Si wafer, so that it has been used a high corrosion resistant ceramic member such as aluminum nitride, alumina, sapphire or the like. As these materials are used for a long time, they are gradually corroded to induce particle generation, so that it has been demanded a material whose corrosion resistance is further improved. For attending such demands, it has been studied to use, as the material, magnesia, spinel (MgAl2O4) or a composite material thereof whose corrosion resistance is higher than that of alumina (For example, Patent document 1; U.S. Pat. No. 3,559,426B).
In a production procedure of a semiconductor device, a semiconductor is adsorbed and held on a wafer mounting face of an electrostatic chuck, and the adsorbed and held semiconductor wafer is subjected to various treatments such as heating or etching treatment. According to an electrostatic chuck, an electrostatic electrode is embedded within a disk shaped ceramic substrate having a wafer mounting face for generating an electrostatic force on the wafer mounting face. A heater electrode (referred to as resistance heating member) is optionally embedded therein for heating the wafer mounting face. As to the ceramic substrate, it has been proposed those made of alumina sintered body and aluminum nitride sintered body, as well as those made of materials with high corrosion resistance against fluorine such as yttria sintered body and magnesia sintered body, for example, considering that the electrostatic chuck is used under condition of contacting a gas containing fluorine. For example, according to Patent Document 2 (Japanese Patent Publication No. 2001-308167A), it is proposed an electrostatic chuck of Johnson-Lahbeck type using a ceramics containing magnesia (MgO) as its main phase. Besides, Patent Document 3 (Japanese Patent Publication No. 2009-292688A), and Patent document 4 (Japanese Patent Publication No. 2006-080116A) are related to magnesium oxide.